I like the samuri idea. That would be a fun theme with samuri warriors, ninjas, horsemen, and other troops with Japanese pill-lock carbines and matchlock muskets or swords and spears. Some of the accesories could be one of those Japanese style castles, complete with trap doors and secret passages, and loopholes for defensive fire. A small Shinto style shrine. Perhaps ships could be made, similar to a Chinese junk or Korean turtle ship in style.
I would also love to see an Egyptian theme... Well, even better, two Egyptian themes released in conjuction. One would be an Ancient Egyptian theme, something akin to the upcoming Roman line. The chariot could be modified to fit the Egyptain decoration scheme.
At the same time, another line could be launched along the lines of the Adventure Theme. It would be late Victorian period (late 1800's) arqueology, with various mummy cases and other ruins. Some of the figure could be British soldiers from the period with their desert tans and topis. Maybe a couple of vehicles could be early cars and trucks or even early airplanes or hot air balloons...